import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

class User{
    public String username;
    public String password;
}


@WebServlet("/getJsonServlet")
public class getJsonServlet extends HttpServlet {

    //  使用jackson 最核心的对象就是ObjectMapper
    //  通过这个对象，就可以把json字符串解析成 java对象
    //  也可以把一个java对象转换成一个 json格式的字符串
    ObjectMapper objectMapper = new ObjectMapper();

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //  通过POST请求的body 传递过来一个json格式的字符串
        User user = objectMapper.readValue(req.getInputStream(),User.class);
        System.out.println("username = " + user.username + "; password = " + user.password);

        resp.getWriter().write("ok");
    }
}
